A contribution to the study of the food of six cyprinid fishes in three areas of the Lake Victoria basin, East Africa

Hydrobiologia ◽  
1979 ◽  
Vol 66 (1) ◽  
pp. 65-72 ◽  
Author(s):  
John S. Balirwa
Keyword(s):  
East Africa ◽  
Lake Victoria ◽  
Lake Victoria Basin ◽  
Cyprinid Fishes

scholarly journals Prolific Lightning and Thunderstorm Initiation over the Lake Victoria Basin in East Africa

2020 ◽  
Vol 148 (5) ◽  
pp. 1971-1985 ◽  
Author(s):  
Katrina S. Virts ◽  
Steven J. Goodman
Keyword(s):  
East Africa ◽  
Hot Spots ◽  
Seasonal Cycle ◽  
Lake Victoria ◽  
Intertropical Convergence Zone ◽  
Lake Victoria Basin ◽  
The Earth ◽  
Total Lightning ◽  
Average Cluster

Abstract The Lake Victoria basin of East Africa is home to over 30 million people, over 200 000 of whom are employed in fishing or transportation on the lake. Approximately 3000–5000 individuals are killed by thunderstorms yearly, primarily by outflow winds and resulting large waves. Prolific lightning activity and thunderstorm initiation in the basin are examined using continuous total lightning observations from the Earth Networks Global Lightning Network (ENGLN) for September 2014–August 2018. Seasonal shifts in the intertropical convergence zone produce semiannual lightning maxima over the lake. Diurnally, solar heating and lake and valley breezes produce daytime lightning maxima north and east of the lake, while at night the peak lightning density propagates southwestward across the lake. Cluster analysis reveals terrain-related thunderstorm initiation hot spots northeast of the lake; clusters also initiate over the lake and northern lowlands. The most prolific clusters initiate between 1100 and 1400 LT, about 1–2 h earlier than the average cluster. Most daytime thunderstorms dissipate without reaching Lake Victoria, and annually 85% of clusters producing over 1000 flashes over Lake Victoria initiate in situ. Initiation times of prolific Lake Victoria clusters exhibit a bimodal seasonal cycle: equinox-season thunderstorms initiate most frequently between 2200 and 0400 LT, while solstice-season thunderstorms initiate most frequently from 0500 to 0800 LT, more than 12 h after the afternoon convective peak over land. More extreme clusters are more likely to have formed over land and propagated over the lake, including 36 of the 100 most extreme Lake Victoria thunderstorms. These mesoscale clusters are most common during February–April and October–November.

Scaling-up sustainable intensification practices for rice production in East Africa

2020 ◽  
Author(s):  
Robert Burtscher ◽  
Taher Kahil ◽  
Mikhail Smilovic ◽  
Diana Luna ◽  
Jenan Irshaid ◽  
...  
Keyword(s):  
East Africa ◽  
Agricultural Production ◽  
Management Practices ◽  
Lake Victoria ◽  
Rice Production ◽  
Sustainable Intensification ◽  
Food Demand ◽  
Suitability Analysis ◽  
Lake Victoria Basin ◽  
Modeling Framework

<p>Food security has long been a challenge for East Africa region and is becoming a pressing issue for the coming decades because food demand is expected to increase considerably following rapid population and income growth. Agricultural production in the region is thus required to intensify, in a sustainable way, to keep up with food demand. However, many challenges face the sustainable intensification of the agricultural production including low productivity, inadequate management, small scale operations, and large climate variability. Several pilot initiatives, that involves a bundle of land and water management practices, have been introduced in the region to tackle such challenges. However, their large-scale implementation remains limited. In the framework of a research project which is jointly implemented by the International Institute for Applied System Analysis (IIASA), the Lake Victoria Basin Commission (LVBC) and the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), we analyse up scaling opportunities for water and land management practices for the sustainable and resilient intensification of rice and fodder production systems in the extended Lake Victoria Basin in East Africa. The expected outcome of this project is to provide an improved understanding of up scaling of such practices through model simulations and integrated analysis of political economy aspects, governance and social and gender dimensions.</p><p>This paper presents an integrated upscaling modeling framework that combines biophysical suitability analysis and economic optimization. Several production system options (i.e., management practices) for rice intensification are examined at high-spatial resolution (0.5°x0.5°) in the extended Lake Victoria basin. The suitability analysis identifies suitable area for the production system options based on a combination of various biophysical factors such as climate, hydrology, vegetation and soil properties using the Global Agroecological Zones (GAEZ) model and the Community Water Model (CWaTM). The economic optimization identifies the optimal combination of those production systems that maximizes their overall contribution to agricultural economic benefits having satisfied various technical and resource constraints including commodity balance, land availability and suitability, water availability, labor availability and capital constraints. A set of socioeconomic (e.g., impact of population and income growth on food demand and agricultural productivity) and climate change (e.g., impact on water resources availability) scenarios based on combinations of the Shared Socioeconomic Pathways (SSPs), Representative Concentration Pathways (RCPs), and co-developed bottom-up policy scenarios, through stakeholders’ engagement with the Basin Commission (LVBC), have been utilized to simulate the modeling framework. Results of this study show the existence of significant opportunities for the sustainable intensification of rice production in East Africa. Moreover, the study identifies the key biophysical and economic factors that could enable the upscaling of sustainable land and water management practices for rice production in the region. Overall, this study demonstrates the capacity of the proposed upscaling modeling framework as a system approach to address the linkages between the intensification of agricultural production and the sustainable use of natural resources.</p>

Genetically distinct strains of Cassava brown streak virus in the Lake Victoria basin and the Indian Ocean coastal area of East Africa

2009 ◽  
Vol 154 (2) ◽  
pp. 353-359 ◽  
Author(s):  
D. R. Mbanzibwa ◽  
Y. P. Tian ◽  
A. K. Tugume ◽  
S. B. Mukasa ◽  
F. Tairo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Coastal Area ◽  
Lake Victoria ◽  
Streak Virus ◽  
Lake Victoria Basin ◽  
Cassava Brown Streak Virus ◽  
The Indian Ocean ◽  
Brown Streak

scholarly journals Implications of Improved Representation of Convection for the East Africa Water Budget Using a Convection-Permitting Model

2019 ◽  
Vol 32 (7) ◽  
pp. 2109-2129 ◽  
Author(s):  
Declan L. Finney ◽  
John H. Marsham ◽  
Lawrence S. Jackson ◽  
Elizabeth J. Kendon ◽  
David P. Rowell ◽  
...  
Keyword(s):  
East Africa ◽  
Water Budget ◽  
Large Scale ◽  
Lake Victoria ◽  
Regional Climate ◽  
Moisture Flux ◽  
Land Breeze ◽  
Moist Convection ◽  
Atmospheric Water ◽  
Lake Victoria Basin

Abstract The precipitation and diabatic heating resulting from moist convection make it a key component of the atmospheric water budget in the tropics. With convective parameterization being a known source of uncertainty in global models, convection-permitting (CP) models are increasingly being used to improve understanding of regional climate. Here, a new 10-yr CP simulation is used to study the characteristics of rainfall and atmospheric water budget for East Africa and the Lake Victoria basin. The explicit representation of convection leads to a widespread improvement in the intensities and diurnal cycle of rainfall when compared with a parameterized simulation. Differences in large-scale moisture fluxes lead to a shift in the mean rainfall pattern from the Congo to Lake Victoria basin in the CP simulation—highlighting the important connection between local changes in the representation of convection and larger-scale dynamics and rainfall. Stronger lake–land contrasts in buoyancy in the CP model lead to a stronger nocturnal land breeze over Lake Victoria, increasing evaporation and moisture flux convergence (MFC), and likely unrealistically high rainfall. However, for the mountains east of the lake, the CP model produces a diurnal rainfall cycle much more similar to satellite estimates, which is related to differences in the timing of MFC. Results here demonstrate that, while care is needed regarding lake forcings, a CP approach offers a more realistic representation of several rainfall characteristics through a more physically based realization of the atmospheric dynamics around the complex topography of East Africa.

scholarly journals Dual-Polarization Radar Observations of Deep Convection over Lake Victoria Basin in East Africa

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 706 ◽  
Author(s):  
Pascal F. Waniha ◽  
Rita D. Roberts ◽  
James W. Wilson ◽  
Agnes Kijazi ◽  
Benedicto Katole
Keyword(s):  
East Africa ◽  
Lake Victoria ◽  
Deep Convection ◽  
Warning System ◽  
Lake Victoria Basin ◽  
Radar Observations ◽  
Low Level ◽  
Weather Events ◽  
Gust Fronts ◽  
Convection Initiation

Lake Victoria in East Africa supports the livelihood of thousands of fishermen and it is estimated that 3000–5000 human deaths occur per year over the lake. It is hypothesized that most of these fatalities are due to localized, severe winds produced by intense thunderstorms over the lake during the rainy season and larger scale, intense winds over the lake during the dry season. The intense winds produce a rough state of the lake (big wave heights) that cause fishing boats to capsize. In this region, weather radars have never been a primary tool for monitoring and nowcasting high impact weather. The Tanzania Meteorological Agency operates an S-band polarimetric radar in Mwanza, Tanzania, along the south shore of Lake Victoria. This radar collects high temporal and spatial resolution data that is now being used to detect and monitor the formation of deep convection over the lake and improve scientific understanding of storm dynamics and intensification. Nocturnal thunderstorms and convection initiation over the lake are well observed by the Mwanza radar and are strongly forced by lake and land breezes and gust fronts. Unexpected is the detection of clear air echo to ranges ≥100 km over the lake that makes it possible to observe low-level winds, gust fronts, and other convergence lines near the surface of the lake. The frequent observation of extensive clear air and low-level convergence lines opens up the opportunity to nowcast strong winds, convection initiation, and subsequent thunderstorm development and incorporate this information into a regional early warning system proposed for Lake Victoria Basin (LVB). Two weather events are presented illustrating distinctly different nocturnal convection initiation over the lake that evolve into intense morning thunderstorms. The evolution of these severe weather events was possible because of the Mwanza radar observations; satellite imagery alone was insufficient to provide prediction of storm initiation, growth, movement, and decay.

scholarly journals Complete Genome Sequences of Rice Yellow Mottle Virus Isolates from the Federal Democratic Republic of Ethiopia

2019 ◽  
Vol 8 (30) ◽  
Author(s):  
Mbolarinosy Rakotomalala ◽  
Bayuh Belay Abera ◽  
Jacqueline Rakotoarisoa ◽  
Dawit Alemu ◽  
Eugénie Hébrard ◽  
...  
Keyword(s):  
East Africa ◽  
Complete Genome ◽  
Democratic Republic ◽  
Lake Victoria ◽  
Mottle Virus ◽  
Rice Yellow Mottle Virus ◽  
Lake Victoria Basin ◽  
Genome Sequences ◽  
Yellow Mottle ◽  
Virus Isolates

The full-length genomes of two isolates of Rice yellow mottle virus from Ethiopia were sequenced. A comparison with 28 sequences from East Africa showed that they clustered within a new strain named S4et, related to the S4mg and S4ug strains found in the Lake Victoria Basin and Madagascar, respectively.

Abstract: Evolution of the Lake Victoria Basin, East Africa

AAPG Bulletin ◽  
1998 ◽  
Vol 82 ◽  
Author(s):  
SCHOLZ, CHRISTOPHER A., Rosenstiel
Keyword(s):  
East Africa ◽  
Lake Victoria ◽  
Lake Victoria Basin

Sites on the landscape: Paleoenvironmental context of late Pleistocene archaeological sites from the Lake Victoria basin, equatorial East Africa

2014 ◽  
Vol 331 ◽  
pp. 20-30 ◽  
Author(s):  
C.A. Tryon ◽  
J.T. Faith ◽  
D.J. Peppe ◽  
W.F. Keegan ◽  
K.N. Keegan ◽  
...  
Keyword(s):  
East Africa ◽  
Late Pleistocene ◽  
Lake Victoria ◽  
Archaeological Sites ◽  
Lake Victoria Basin

scholarly journals Regional nitrogen budget of the Lake Victoria Basin, East Africa: syntheses, uncertainties and perspectives

2014 ◽  
Vol 9 (10) ◽  
pp. 105009 ◽  
Author(s):  
Minghua Zhou ◽  
Patric Brandt ◽  
David Pelster ◽  
Mariana C Rufino ◽  
Timothy Robinson ◽  
...  
Keyword(s):  
East Africa ◽  
Lake Victoria ◽  
Nitrogen Budget ◽  
Lake Victoria Basin
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